coalesce dep-info-spaces and dep-info-doesnt-run-much into dep-info

Author: Oneirical

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -1,8 +1,5 @@
 run-make/branch-protection-check-IBT/Makefile
 run-make/cat-and-grep-sanity-check/Makefile
-run-make/dep-info-doesnt-run-much/Makefile
-run-make/dep-info-spaces/Makefile
-run-make/dep-info/Makefile
 run-make/emit-to-stdout/Makefile
 run-make/extern-fn-reachable/Makefile
 run-make/incr-add-rust-src-component/Makefile

tests/run-make/dep-info-doesnt-run-much/Makefile

@@ -0,0 +1,36 @@
+// This is a simple smoke test for rustc's `--emit dep-info` feature. It prints out
+// information about dependencies in a Makefile-compatible format, as a `.d` file.
+
+// This test first checks that emitting dep-info disables static analysis, preventing
+// compilation of `erroneous.rs` from causing a compilation failure.
+// Then, it checks that compilation using the flag is successful in general, even with
+// empty source files or source files that contain a whitespace character.
+
+// Finally, it removes one dependency and checks that compilation is still successful.
+// See https://github.com/rust-lang/rust/pull/10698
+
+use run_make_support::{rfs, rustc};
+
+fn main() {
+    // We're only emitting dep info, so we shouldn't be running static analysis to
+    // figure out that this program is erroneous.
+    rustc().input("erroneous.rs").emit("dep-info").run();
+
+    rustc().input("lib.rs").emit("dep-info,link").crate_type("lib").run();
+    rfs::remove_file("foo.rs");
+    rfs::create_file("foo.rs");
+    // Compilation should succeed even if `foo.rs` is empty.
+    rustc().input("lib.rs").emit("dep-info,link").crate_type("lib").run();
+
+    // Again, with a space in the filename this time around.
+    rustc().input("lib_foofoo.rs").emit("dep-info,link").crate_type("lib").run();
+    rfs::remove_file("foo foo.rs");
+    rfs::create_file("foo foo.rs");
+    // Compilation should succeed even if `foo foo.rs` is empty.
+    rustc().input("lib_foofoo.rs").emit("dep-info,link").crate_type("lib").run();
+
+    // When a source file is deleted, compilation should still succeed if the library
+    // also loses this source file dependency.
+    rfs::remove_file("bar.rs");
+    rustc().input("lib2.rs").emit("dep-info,link").crate_type("lib").run();
+}